Lisa Zeppegno waited for help for two agonizing hours with a broken back after her horse threw her when startled by mountain bikers on a Novato trail in June. But she never lost her spirit, and a fundraiser Saturday night went a long way toward helping her heal.

"Help Us Heal," the fundraiser organized by the Marin Horse Council for Zeppegno, 44, of Oakland and her riding companion, Nicole Devito, 47, also of Oakland, drew about 400 people to the Novato Horsemen's clubhouse and raised an estimated $15,000, organizers said. Marin County Supervisors Steve Kinsey and Judy Arnold attended.

"This was the worst thing that has ever happened to me, but it is also the best thing," said Zeppegno, who spends most of her time lying on her side on the couch these days. "I am overwhelmed by the generosity and kindness that surrounded me last night. Hundreds of people came up to me with well wishes and stories of their own recovery from injuries."

Zeppegno and Devito were hurt when their horses spun around and fled as two mountain bikers came flying around a blind corner on a narrow trail in the remote Indian Tree Preserve near the end of Vineyard Road on June 20. The two young mountain bikers have not been identified.

"Horses are prey animals. They thought (the mountain bikers) were coming to kill them," Zeppegno said of the incident. "Coco (Zeppegno's mount) ran for her life down the ravine." Coco suffered deep gashes on her nose and in her armpit.

Devito, who was not hurt as badly as her friend, was able to dial 911 on her cellphone, but it took two hours for paramedics from the Novato Fire Department to reach the remote, wooded location. Firefighters then summoned a Sonoma County Sheriff's Office helicopter.

Zeppegno, a self-employed acupuncturist and independent contractor for Kaiser, said, "I knew right away my back was badly injured. The pain was excruciating." She had compression fractures of her L1 and L2 lumbar vertebrae and her sacrum, the bone at the base of her spine.

It could take six to eight months for Zeppegno to regain normal mobility, and in the meantime, she is unable to do her acupuncture work. The funds raised at the event will help pay her medical expenses. She hopes to begin physical therapy soon.

"I don't hold any animosity" toward the mountain bikers, Zeppegno said. "The biggest thing is education to prevent mountain bikers from riding illegally. There are certain trails that are OK for them to ride, but some that are not."

Historically, there has been conflict between bicycle groups and equestrian groups, but for about a year now the two have been working together on issues including trail safety. The newly formed bond between the two held even in the face of the June 20 incident.

"From just about the moment of the accident, the Marin County Bicycle Coalition has worked with the Marin Horse Council to do whatever we could to help," said Curt Kruger, the trail committee chair for the council.

About 50 members of Marin's bicycle community attended Saturday's fundraiser, according to Tom Boss, off-road and events director of the bicycling group.

"We were invited to participate in the event because we have been working with the Horse Council on education. We have outlined a safety curriculum that includes a code of conduct for all trail users and we are talking about hosting workshops where cyclists and equestrians can learn together," Boss said.

"The Saturday fundraiser brought in $15,000, and $3,000 of that came from the bicycle community," said Kruger.

"I'm so grateful for what everyone has done for me," Zeppegno repeated over and over. "The nurses at the San Rafael Kaiser emergency room were so wonderful to me, and so were the paramedics who came to my rescue."

Devito, her riding companion, drove Zeppegno to the fundraiser and has been one of her biggest support people during recovery. Novato Horsemen donated use of the facility for the fundraiser, and local veterinarian Jim Williams prepared the food along with Scott and Laura Colvin, members of Novato Horsemen.

"It (the fundraiser) was an outpouring of support I will never forget," Zeppegno said. "I can't believe all the work that went into this. It was heartwarming. It made me feel there is good in the world."